### hydrodynamic equations

(equations describing the dynamics of fluids)

**Hydrodynamic equations** are equations that describe fluid dynamics,
relating velocity, mass, momentum, and pressure.
The Navier-Stokes equations provide a very general framework,
which may be made more specific by plugging in the characteristics
of the forces, e.g., for fluids on astronomical body such as
its atmosphere or liquid bodies, for gravity.
For (approximately) spherically-symmetric flows, e.g., the
solar wind, it can be the equation of hydrostatic equilibrium
with an added term to cover the motion.

(*fluid dynamics,hydrodynamics*)
http://en.wikipedia.org/wiki/Fluid_dynamics

http://glossary.ametsoc.org/wiki/Hydrodynamic_equations_of_motion

http://www.ita.uni-heidelberg.de/~dullemond/lectures/num_fluid_2012/Chapter_1_improved.pdf

https://math.mit.edu/~dunkel/Teach/18.354_2014S/lecture_notes/L06_L07_hydrodynamics.pdf

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